Smooth-billed Duck Orchid

Caleana terminalis has a single smooth, dull green or dull red leaf, 20–30 mm (0.8–1 in) long and 5–7 mm (0.2–0.3 in) wide. Unlike those of most other species of Caleana, the leaf is not withered at flowering time. Usually only one greenish yellow and red flower, 15–22 mm (0.6–0.9 in) long and 10–14 mm (0.4–0.6 in) wide is borne on a thin, wiry stalk 80–140 mm (3–6 in) high. The dorsal sepal, lateral sepals and petals are narrow and hang downwards with the dorsal sepal pressed against the column which has broad wings, forming a bucket-like shape. About one fifth of the outer part of the labellum is covered with glossy black glands or calli and the labellum has a slightly humped top. Flowering occurs in August and September.

Caleana terminalis grows in sandy soil in shrubland between the Pinjarega Nature Reserve and Nerren Nerren station in the Geraldton Sandplains biogeographic region.